Betaine derivatives of bis-imidazoline compounds

ABSTRACT

Fabric softening agents in the form of betaine derivatives of bisimidazoline compounds, the latter characterized in having a long chain aliphatic substituent in the 2 and 2&#39;&#39; positions of the respective rings and wherein the 1, 1&#39;&#39; linking entity is an alkylene radical or polyalkylene segments internally joined by an amino or amido nitrogen atom(s).

United States Patent McConnell Aug. 5, 1975 [541 BETAINE DERIVATIVES OF 2,773,068 12/1956 Mannheimer 260/3096 2,982,651 5/1901 Mackey 260/309.6 X 3,152,080 10/1964 Stuart (it 211. 260/309.6 [75] Inventor: R rt M C nn l Janesville. 3,629,104 12/1971 Maddox, Jr..... 260/3096 x Wis. 7 3,855,235 12/1974 McConnell 260/3096 [73] Assignee: Ashland Oil, Inc., Ashland, Ky.

Primary Exuminew-Ethel G. Love 22 Fi1ed2 Dec. 17, 1973 7 Fabric softening agents in the form of betaine deriva- [52] 260/309'6; "52/88; 117/1395 CO tives of bisimidazoline compounds, the latter charac- [51] hit. C1. C07D 49/34 terized in having a g Chain aliphatic Substituent in [58] Field of Search 260/309.6 the 2 and positions of the respective rings and wherein the 1, 1 linking entity is an alky1ene radical [56] References cued or polyalkylene segments internally joined by an UNITED STATES PA amino or amido nitrogen at0m(s).

2,374,354 4/1945 Rutherford 260/309.6 2,568,876 9/1951 White et a1. 260/3096 x 14 Clams N0 Drawmgs BETAINE DERIVATIVES OF BlS-IMIDAZOLINE COMPOUNDS BACKGROUND OF THE INVENTION 1. Field Of The Invention This invention relates to amphoteric derivatives of a class of bisimidazolines provided by the cyclization of condensation products of certain polyalkylene amines with fatty acids or functional equivalents thereof.

2. Description Of The Prior Art Mono-imidazolines substituted in the number 2 position thereof with a long chain aliphatic group are well known in the art. These compounds are cationic substances exhibiting surface active properties to the extent of rendering them useful cationic emulsifiers, flotation agents, corrosion inhibitors and the like. The quaternary derivatives of these compounds find extensive use in fabric softening applications whereas the ampholytes derived therefrom have been used mainly as surface active agents in a variety of cleaning formulations. The imidazolines are of particular interest because they can be more readily and economically prepared than the aliphatic amines of comparable molecular weight and functional effectiveness in the uses noted.

The mono-imidazoline compounds referred to above are prepared by first condensing a higher fatty acid with a polyamine containing a secondary amine group. Following the foregoing step which leads to the formation of an amido substituted alkylene amine, same is cyclized to yield the imidazoline structure. Where the cyclized product contains a terminal primary amine group in the aliphatic residue such as those derived, for example, from diethylene triamine, it is known that these compounds can be advantageously modified by further condensation with a fatty acid in those instances where the contemplated use of the product is in a fabric softening application.

It has also been proposed by the prior art to prepare bisimidazoline compounds via the process noted above. In order to achieve the bis structure a starting polyamine is called for having at least two secondary amine groups each in a gamma position with respect to a primary amine group. Exemplary of this prior art is U.S. Pat. No. 3,244,724 which further teaches that the sulfopropylated derivatives of a variety of alkylene bisimidazolines exhibit fabric softening properties. Nonetheless, it is recognized that such softeners fail to measure up to the performance associated with the present day softeners of commerce including the imidazoline type. Accordingly, there is an existing need for an amphoteric type fabric softening agent whose effectiveness more closely corresponds to that exhibited by the quaternary ammonium type softeners of commerce.

SUMMARY OF THE INVENTION In accordance with the present invention, carboxy alkylated derivatives of a class of bisimidazoline compounds are provided wherein the indicated compounds correspond to the following structural formula:

wherein R is a C -C hydrocarbyl group; n is an integer of from 0-4; R is a C -C alkylene group; and A is hydrogen or an acyl group of the formula:

in which R has the meaning as aforesaid.

The foregoing ampholytes are characteristically compatible with the anionic surfactants prevalently employed in heavy duty detergent compositions for household fabric washing application. Thus they can be used in the wash cycle of washing operation with the advantage that an adjuvant amount thereof comparable to that observed in the use of the quaternary ammonium type softener will result in like softening effectiveness.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The preparation of imidazoline compounds of the type concerned herein basically involves the reaction of a higher fatty acid or functional equivalent thereof with a polyamine. The implementation of the present invention, however, calls for the use of a specific type of polyamine. Such polyamines are those having-the following structural formula:

wherein R represents a C C. alkylene group, preferably ethylene. The preferred polyamine is triethylenetetramine. The latter amine, as well as those otherwise corresponding to the structural formula given, are comme'rcially available. They are reported to be prepared by the ammonolysis of either an alkylene dichloride or an olefin; specifically ethylene, for realizing the preferred polyamines.

With respect to the applicable fatty acid reactants, substantially more latitude is afforded in the selection thereof as compared to the polyamine. Broadly, the C fatty acids are suitable for deriving the bisimidazoline compounds useful in the practice of this invention. Representative of such fatty acids include: caproic, heptanoic, caprylic, capoic, decenoic, undecanoic, lauric, dodecenoic, tridecanoic, myristic, tetradecenoic, pentadecenoic, hexadecenoic, palmitic, heptadecenoic, stearic, oleic, nonadecanoic, eicosanoic, behamic, tetracosanoic and the like. The preferred fatty acids are the mixtures thereof derived from tallow, soybean or coconut oil. Tall oil fatty acids are exemplary of a naturally occurring mixture of acids suitable for the instant purposes.

Particularly preferred for obtaining the contemplated bisimidazoline compounds is the mixture of fatty acids constituting tallow. The fatty acid reactant can take the form of the fatty acid itself, and alkyl ester thereof or the naturally occurring glyceride esters. As will be noted below, the glyceride ester form of the fatty acid will readily split in the course of the initial condensation of the acid and the polyamine reactant and the glycerol by-product can be removed from the reaction mixture. Since the naturally occurring glyceride form of the indicated animal and vegetable derived fatty acids are 'more economical than the free acids or the mono esters,,- it ispa'rticularly preferred to use these fatty acids in thisform. In connection with this discussion of the suitable fatty'acids for use in the practice of this invention, it is to be noted that the R substituent collectively represents the mixture of hydrocarbyl resi dues associated with carboxyl groups of said fatty acids.

In effecting the initial condensation of the fatty acid and the polyamine such are merely heated at about 100 to 200C, preferably employing a nitrogen sparge when the fatty acid is in the'forrn of the free acid or mono ester thereof. In the case of utilizing the triglyceride form of the fatty acid, it is preferred to carry out the condensation at a slight pressure or under a mild reflux condition. In preparing the unmodified bisimidazolines contemplated herein, the selected polyamine and fatty acids are reacted in a relationship of about 0.9 to 1.5 moles of the polyamine for 2 moles of the fatty acid. Of course, when the triglyceride form of the fatty acids is used, one will employ two-thirds of a mole thereof in order to provide the 2 moles of fatty acid for combining with the polyamine in the relationship selected. As indicated, where a triglyceride oil is used, splitting to effect the in situ formation of the polyamido amine is readily accomplished in the reaction system concerned. In those instances where the linking entity of the contemplated bisimidazolines contains one or more secondary amine groups such can be further modified completely or partially by reaction with a fatty acid or again a functional equivalent thereof such as a triglyceride oil. This type of further modification can be achieved after the cyclization step described hereinbelow or sufficient added fatty acids can be included in the initial reaction product in order to achieve the extent of modification desired. The latter procedure is preferred.

The next step in deriving the bisimidazolines involves cyclizing thepolyamido amine. This reaction is accomplished by heating the polyamido amine at a temperature between about 125 and 250C under vacuum. Subatmo spheric pressure conditions in the order of from I to 300 mm Hg suffice for this purpose. In those instanceswhere the free fatty acid or a lower alkyl ester thereof is employed as a reactant, the use of moderate vacuum in the order indicated is generally observed. Where, however, the polyamido amine is derived from a triglyceride ester, it is advantageous to operate at the low levels of the indicated pressure range in order to effect the removal of the glycerine. The extent of cyclization can be noted by analyzing for the tertiary amine content, generally referred to as the TAN value of the reaction mixture.

Carboxyalkylation of the aforedescribed bisimidazolines can be carried out in a conventional manner. Generally, it is desirable to conduct the reaction by having the bisimidazoline in the form of a concentrated dispersion thereof in an inert anhydrous organic solvent. Suitable inert solvents include the various lower alkanols and glymes. Isopropanol is especially preferred for this purpose. The reaction can be carried out by adding the alkylating agent to a stirred concentrate of the bisimidazoline. The solid contents of the concentrate for effecting this reaction can range from about 50 to 90 weight percent, but more usually is about 65 to 85 percent on a weight basis. Temperatures applicable for this purpose range from room temperature to about 125C depending upon the volatility characteristics of the inert solvent employed.

The agents useful for deriving the alkylated product include the halo fatty acids containing from 2 to 4 carbon atoms. The halo substituent, as usual in a reaction of this type, can be chloro, bromo or iodo. The chloro acids are preferred with chloroacetic acid representing the preferred agent. The alkylation reaction is carried out employing an alkali metal salt of the halo acid. Alternatively, the indicated salts can be formed in situ by the addition of the acid and base to the alkylation reaction mixture.

In order to illustrate to those skilled in the art how the present invention can be practiced and utilized, the following working examples are given. As indicated, these examples are set forth primarily for the purpose of illustrating the best mode contemplated for carrying out the present invention. Therefore, any enumeration of details contained therein should not necessarily be interpreted as a limitation on the invention as the only limitations intended are those expressed in the appended claims. All parts and percentages are by weight unless otherwise stated.

EXAMPLE I Into a suitable reaction vessel equipped with a stirrer and thermometer were charged 146.24 parts (1 mole) of triethylene tetramine and 574 parts (0.667 mole) of bleached soft tallow. With stirring, the reaction mixture was heated at 150C with a nitrogen sparge for 3 hours to form the polyamidamine condensation product. Following this reaction period, the apparent molecular weight was 885 and little unreacted triglyceride was indicated by infrared analysis. The di-amido-amine was then heated to l60195C at 15mm Hg whereupon glycerine and water were removed over a 2-hour period until the tertiary amine content (TAN) of the cyclization product was in excess of 90 weight percent. The resultant bisimidazoline product was cooled to 65C and 596 parts of isopropanol added followed by the addition of 244 parts (2.1 moles) of sodium chloroacetic acid and 15.7 parts water. The reaction mixture was refluxed at a liquid temperature of 8095C for l 1 hours. After filtering to remove sodium chloride, the product analyzed 0.6 wt. free amine content'The pH of the dispersion was 5.7.

EXAMPLE II The semi-liquid concentrate (64 wt. solids) of Exdispersed in 221.8g of 140F tap water with high speed mechanical agitation to give a 5 wt. solids dispersion. The dispersion showed excellent stability at 40, and l-20F and remained stable after one month of storage. Conventional softening and rewet tests were conducted using the aforedescribed dispersion, details of which and the results obtained are set forth as follows.

An 8 lb. dry load of fabric consisting of four desized white eotton-dacron sheets and four desized white cottom towels was washed in a household top loading washer set for a regular warm water cycle in the presence of 35gms of a commercial heavy duty detergent. Upon commencement of the rinse cycle 70 gms of the 5% softener dispersion were added to provide 0.096 wt. active softener based on the weight of the fabric. Following the rinse cycle, the wash load was removed and line dried at room temperature for 24 hours. The

treated fabrics were then panel rated using an arbitrary scale of l-4, in which 1 represents the rating assigned to untreated fabric and the value 4 represents the soft est rating; that is, the softness associated with the test fabric rinsed three time with 0.3 wt. based on cloth of dimethyl distearyl ammonium chloride as the softener. In accordance with this testing procedure, the softener product of Example I were assigned ratings of 3.2. By comparison, commercial rinse cycle softeners usually give ratings on the range of 2.5 to 3. The material was also similarly evaluated at 0.4 wt. (290g of 5% dispersion) in the wash cycle and gave ratings of 3.0. Commercial wash cycle softeners usually give ratings of 2 to 2.75.

Rewetting was evaluated using a standard wicking test. Swatches (4 in. X 2 in.) were cut from the softened towels and were suspended such that the edge was barely submerged in a dyed water solution. The water solution was permitted to migrate up the swatch for a period of 6 minutes. The extent of migration was then measured in millimeters. Readings for untreated towel samples averaged 75mm whereas towels treated with dimethyl distearyl ammonium chloride gave readings in the order of 20mm (0.083 wt. in rinse cycle) and 5mm (0.4 wt. in wash cycle). In comparison, the softener product of Example I gave readings of 49mm in the rinse cycle and 47.8mm in the wash cycle.

EXAMPLE III Triethylenetetramine in the amount of 150 parts (1.02 moles) was reacted with 440 parts (0.667 mole) of refined coconut oil following the procedure outlined in Example I. The resulting dicoco bisimidazoline in the amount of 504 parts (0.75 mole) was reacted with 198 parts (2.1 moles) of chloroacetic acid and 84 parts Na OH in 424 parts isopropanol at 80 to 95C until the free amine content dropped to less than 1 wt. Upon diluting with water in accordance with the procedure described in Example II, a 5 wt. dispersion was obtained. The material, when tested as in Example 11, gave softening ratings of 2.5 in the rinse cycle.

EXAMPLE IV In accordance with the procedure of Example I, tetraethylenepentamine in the amount of 189.24 parts 1 mole) was reacted with 860 parts (1 mole) of bleached soft tallow at 150C for 3 hours to provide the trialkyl amidoamine. Following this reaction, the apparent molecular weight was 1 105, and infrared analysis indicated a minimal amount of unreacted triglyceride. The triamidoamine was heated to 160 to 195C at mm Hg whereupon glycerine and water were removed over a 2-hour period until the tertiary amine content was in excess of 90%. The resultant bisimidazoline in the amount of 977 parts (1 mole) was dissolved in 689 parts of isopropanol and reacted with 244 parts (2.1 mole) of sodium chloroacetic acid in the presence of 1% water as in Example I until the free amine content dropped to less than 2 wt. The resulting product gave softening results substantially the same as those observed in a like evaluation of the compound of Example I.

What is claimed is:

1. An amphoteric fabric softening agent having the formula:

R H A R,

wherein R is a C --C hydrocarbyl group; n is an integer of from 1-3; m is an integer of from 04; R is a C C alkylene group; A represents hydrogen or an acyl group of the formula R,C (O) in which R has the meaning as aforesaid.

2. A compound in accordance with claim 1 wherein R is ethylene.

3. A compounmd in accordance with claim 2 wherein m is l.

4. A compound in accordance with claim 3 wherein A is hydrogen.

5. A compound in accordance with claim 3 wherein A is said acyl group.

6. A compound in accordance with claim 2 wherein m is O.

7. A compound in accordance with claim 5 wherein R represents the hydrocarbyl residues of the carboxyl moiety of tallow fatty acids.

8. A compound in accordance with claim 6 wherein R represents the hydrocarbyl residues of the carboxyl moiety of tallow fatty acids.

9. A compound in accordance with claim 6 wherein R represents the hydrocarbyl residues of the carboxyl moiety of coconut fatty acids.

10. A compound in accordance with claim 1 wherein n=l.

11. A compound in accordance with claim 6 wherein n=1.

12. A compound in accordance wtih claim 7 wherein n=l. V

13. A compound in accordance with claim 8 wherein n=l.

14. A compound in accordance with claim 9 wherein n=l. 

1. AN AMPHOTERIC FABRIC SOFTENING AGENT HAVING THE FORMULA:
 2. A compound in accordance with claim 1 wherein R is ethylene.
 3. A compounmd in accordance with claim 2 wherein m is
 1. 4. A compound in accordance with claim 3 wherein A is hydrogen.
 5. A compound in accordance with claim 3 wherein A is said acyl group.
 6. A compound in accordance with claim 2 wherein m is
 0. 7. A compound in accordance with claim 5 wherein R1 represents the hydrocarbyl residues of the carboxyl moiety of tallow fatty acids.
 8. A compound in accordance with claim 6 wherein R1 represents the hydrocarbyl residues of the carboxyl moiety of tallow fatty acids.
 9. A compound in accordance with claim 6 wherein R1 represents the hydrocarbyl residues of the carboxyl moiety of coconut fatty acids.
 10. A compound in accordance with claim i wherein n
 1. 11. A compound in accordance with claim 6 wherein n
 1. 12. A compound in accordance wtih claim 7 wherein n
 1. 13. A compound in accordance with claim 8 wherein n
 1. 14. A compound in accordance with claim 9 wherein n l. 